A new study finds that introductory psych textbooks are painting a too-rosy picture of the science.

When I was an undergraduate psychology major, I was captivated by the quirky findings from psychology experiments that appeared in my textbooks. Nuggets like these:

People who read “old”-sounding words (like “nursing home”) were more likely to walk slowly — showing how our brains can be subtly “primed” with thoughts and actions.

Merely activating muscles around the mouth caused people to become happier — demonstrating how our bodies tell our brains what emotions to feel.

Minorities and maligned social groups don’t perform as well on tests due to an idea called “stereotype threat.”

Studies like these made me want to continue studying psychology. And their implications were largely hopeful: They suggested that the mind — as self-defeating as it can be — can be understood, corrected, and perhaps mastered.

Alas, the past few years have not been kind to social psychology. Many psychological theories have been debunked or diminished in rigorous replication attempts. Psychologists are now realizing it’s more likely that false positives will make it through to publication than inconclusive results. And they’ve realized that experimental methods commonly used just a few years ago aren’t rigorous enough. Many topics in psychology are opening up to debate.

But troublingly, the textbooks have not been updated accordingly.

That’s the conclusion of a recently published study in Current Psychology.* “By and large,” the study explains (emphasis mine):

“introductory textbooks have difficultly accurately portraying controversial topics with care or, in some cases, simply avoid covering them at all. … readers of introductory textbooks may be unintentionally misinformed on these topics.”

(*I found this study via New York magazine’s Jesse Singal, whose piece and overall coverage of psychology’s replication woes you should also read.)

The study authors — from Texas A&M and Stetson universities — gathered a stack of 24 popular introductory psych textbooks and began looking for coverage of 12 contested ideas or myths in psychology.

The ideas — like stereotype threat, the Mozart effect, and whether there’s a “narcissism epidemic” among millennials — have not necessarily been disproven. Nevertheless, there are credible and noteworthy studies that cast doubt on them. The list of ideas also included some urban legends — like the one about the brain only using 10 percent of its potential at any given time.

The researchers then rated the texts on how they handled these contested ideas. “Biased” coverage was defined as only presenting one side of the argument. “Partially biased” means the text noted the debate “but only peripherally.” “Unbiased” means the textbook “provided fair, comprehensive and accurate coverage of both sides.”

The results found a troubling amount of “biased” coverage on many of the topic areas.

There are some striking examples. For one: The debate over whether violent media can make people violent rages on to this day. However, 50 percent of the textbooks only presented one side of the debate.

But why wouldn’t these textbooks include more doubt? Replication, after all, is a cornerstone of any science.

One idea is that textbooks, in the pursuit of covering a wide range of topics, aren’t meant to be authoritative on these individual controversies.

But something else might be going on. The study authors suggest these textbook authors are trying to “oversell” psychology as a discipline, in order to get more undergraduates to study it full time. Take the cheeky headline of the paper: “Education or Indoctrination? The Accuracy of Introductory Psychology Textbooks in Covering Controversial Topics and Urban Legends About Psychology.” (I have to admit that it may have worked on me back when I was an undeclared undergraduate.)

There are some caveats to mention with the study: One is that the 12 topics the authors chose to scrutinize are completely arbitrary. “And many other potential issues were left out of our analysis,” they note. Also, the textbooks included were printed in the spring of 2012. It’s possible they have been updated since then.

But if it’s true that textbooks are still neglecting to cover replication issues, then I’d argue they are actually underselling the science.

Students might be heartened to learn (like I was) that there are researchers thinking very hard, and very earnestly, on trying to make psychology a more replicable, robust science. (There’s even a whole Society for the Improvement of Psychological Science devoted to these issues.)

To teach the “replication crisis” is to teach students that science strives to be self-correcting. It would instill in them the value that science ought to be reproducible.

Understanding human behavior is a hard problem. Finding out the answers shouldn’t be easy. If anything, that should give students more motivation to become the generation of scientists who get it right.

“Textbooks may be missing an opportunity for myth busting,” the study’s authors write. That’s, ideally, what young scientist ought to learn: how to bust myths and find the truth.